Re: [Phys-L] apparent weight

["John Clement" <clement@hal-pc.org>]

The lighter scale reading will happen for both the Sun above and the Sun
below, just as the Moon produces 2 tides.  This simple analogy argument
might be helpful with students.  The simple physics explanation is that
since you are closer to the Sun when above than the center of the Earth, you
have a greater acceleration toward the sun.  When the sun is below the Earth
is accelerating more towards the sun than you are because it is closer to
the Sun.  In both cases this results in a lower scale reading. I will leave
the complicated explanations to others, as they will confuse most students.
Unfortunately most simple accounts of the tides ignore the true effect and
just talk about the pull.  It is a gradient effect.

Of course a simple bathroom scale would be inadequate for seeing this
effect, and a gym scale which is a balance would show no effect.

John M. clement
Houston, TX
 

> If you stand on a sensitive scale, will you be slightly 
> lighter at noon (with the Sun above you and pulling opposite 
> to Earth's gravity), and slightly heavier at midnight (with 
> the Sun below you and pulling in the same direction as 
> Earth's gravity)? Ignore any lunar effects.
>
> This came up the other day, and nobody could really agree. 
> One side said no because the Earth is in freefall around the 
> Sun, and it is the Earth that pulls us to it. The other side 
> said yes due to tidal effects as seen in the oceans.
>
> I searched online, and found the same conflicting arguments!
>
> Can anyone help with this?
>
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